Conveyor system for trays

ABSTRACT

A conveyor system in which carriers such as trays are propelled along a support by pusher units on an endless driven chain and can be stopped, accumulated and transferred from one chain to another. Each pusher unit includes a pusher member engageable with a driving flange on a carrier and retained in driving position by a locking member which projects into the path of carrier movement in advance of the pusher member and the carrier driven thereby and is engageable with an object in the path of movement to release the pusher member and permit the stopping and accumulation of carriers.

United States Patent Pachuta CONVEYOR SYSTEM FOR TRAYS [72] Inventor: Martin Pachuta, Allen Park, Mich. [73] Assignee: Jervis B. Webb Company [22] Filed: Jan. 21, 1970 [21] Appl No.: 4,633

[ 1 May 9,1972

Lingg ..l ..104/172 5 Follrath ..104/172 5 [5 7] ABSTRACT A conveyor system in which carriers such as trays are propelled along a support by pusher units on an endless driven chain and can be stopped, accumulated and transferred from one chain to another. Each pusher unit includes a pusher member engageable with a driving flange on a carrier and retained in driving position by a locking member which projects into the path of carrier movement in advance of the pusher member and the carrier driven thereby and is engageable with an object in the path of movement to release the pusher member and permit the stopping and accumulation of carriers.

14 Claims, 5 Drawing Figures PATENTEDHAY 91972 3,661,094

E g 5i HWENTOR MART/N PAC/V0734 W a BY ATTORNEYS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in a conveyor system of the type in which load carriers are engaged and propelled along a support by pushers on an endless chain mounted adjacent to the support. The improvements of the invention are particularly directed to a system where trays or similar containers are used as load carriers.

2. Description of the Prior Art One prior form of pusher conveyor for trays consists of a pair of rails which guide and support the trays, and a chain mounted below and between the rails provided with upstanding rigid pushers each engageable with the rear end of a tray. This form of conveyor is limited in use to the continuous propulsion of trays by a single chain along rails where frictional resistance to the movement of the trays is great enough to insure that a tray will not move faster than the pusher which is propelling it.

SUMMARY OF THE INVENTION The present invention overcomes certain limitations of prior tray conveyors and provides a conveyor system in which trays can be propelled horizontally and up and down inclines with a positive coupling to a pusher unit of the propelling member, and can be stopped, accumulated, and transferred from one propelling member to another as required in a particular installation.

The conveyor system of the invention consists essentially in the combination of a plurality of trays, each tray having a bottom portion with driving means thereon; tray supporting and guiding structure defining a path of tray travel; a propelling member and means mounting the propelling member for travel below the bottom portion of trays on the tray supporting structure; and a plurality of pusher units connected to the propelling member in spaced relation along the length thereof. Each pusher unit includes a pusher member and a locking member, the pusher member having a driving dog and a positioning arm, the locking member having a locking portion and a tripping arm; and, the pusher member is supported for movement between a normal driving position in which the driving dog is engageable with the driving means on a tray and a non-driving position, while the locking member is separately supported for movement between a'normal locking position in which the locking portion of the locking member engages the positioning arm of the pusher member and a released position. In the normal locking position, the locking member prevents movement of the pusher member to non-driving position, and the tripping arm of the locking member extends into the path of tray movement in advance of a tray whose driving means is engaged by the driving dog of the pusher member.

The construction of each pusher unit is relatively simple and inexpensive while ofiering the combined advantages of positive driving action and pusher member releasing action for the stopping and accumulation of trays.

Preferrably the driving means on each tray comprises a recessed shoulder formed in the bottom of the tray and extending transversely between the sides thereof, enabling a tray to be diverted laterally, while propelled by a pusher member, from the path of one propelling member and into the path of another to permit the positive transfer of trays to such other propelling member as desired.

Other features and advantages of the invention will appear from the description of the presently preferred embodiment disclosed in the accompaning drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing a portion of a conveyor system constructed in accordance with the invention;

FIG. 2 is a sectional elevation on an enlarged scale, taken as indicated by the line 2-2 of FIG. 1;

FIG. 3 is a sectional elevation taken as indicated by the line 3-3 of FIG. 1;

FIG. 4 is an enlarged side elevation of a pusher unit and portions of a pair of trays, and

FIG. 5 is a fragmentary sectional elevation taken on the line 5-5 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The conveyor system illustrated is capable of moving load carriers in the form of trays 10 along a path of travel defined by tray supporting and guiding structure. This structure consists of a pair of horizontally spaced supporting rails 12 and 14 each fastened at suitable intervals to vertical posts 16 which are secured to frame members 18; and, a pair of horizontally spaced guide rails 20 and 22 each secured to upright members 23 carried by the frame members 18. These guide rails 20 and 22 are positioned above the horizontal level of supporting rails 12 and 14 and are engageable bythe rim portion 24 of a tray 10.

Each tray 10 has a bottom 26 engageable with the supporting rails 12 and 14 and provided with driving means 28 consisting of a recessed shoulder formed in the bottom of the tray 10 adjacent each of the ends 30 and 31 thereof and extending transversely of the tray between the sides 32 thereof. Each recessed shoulder includes a center portion 33 (FIG. 1) which extends substantially normal to the longitudinal center line of the tray 10 and a pair of angular side portions 34 which converge toward the adjacent end of the tray.

An endless propelling member 36, having pusher units 38 mounted thereon at longitudinally spaced intervals, is suitably supported for travel below the tray supporting rails 12 and I4, and is driven by a conventional type of drive unit (not shown). In the construction illustrated, the propelling member is in the form of a chain having alternate pairs of vertically disposed links 40 and horizontally disposed links 42 connected by pins 43. A pair of supporting wheels 44 is carried by the vertical links 40 and a single guide wheel 45 by the horizontal links 42. This chain travels in an inclosed track 46 supported by the frame members 18, alternate forms of track construction being shown. In FIGS. 2 and 3, the track 46 has a continuous slot 47 formed in one of the sides thereof, while in FIGS. 4 and 5, the track has a continuous slot 48 formed in the top thereof, and in either case the mounting means for each pusher unit 38 extends through the slot.

Each pusher unit 38 includes a U-shaped bracket 50, con nected to a horizontal link 42 of the chain by an arm 51 (FIGS. 2 and 3) or by a vertically extending portion 52 (FIGS. 4 and 5), and supporting a pusher member 54 and a locking member 56 on pivots 57 and 58 respectively, the locking member 56 being mounted forwardly of the pusher member 54 with relation to the direction of travel indicated by the arrow 59 in FIG. 4. The pusher member 54 includes an arm 60 with an upstanding driving dog 61 and holdback dog 62, the holdback dog projecting in the direction of the plane defined by the supporting rails 12 and 14 a distance less than the driving dog and being normally non-engageable with a tray as best shown in FIG. 4. The pusher member 54 also includes a positioning arm 64 which extends forwardly of the pusher member pivot 57, and which acts as a counterweight to normally urge the pusher member 54 to a driving position illustrated in FIG. 4, this gravity biased movement of the pusher member being limited by a stop 66.

Each locking member 56 has a tripping arm 68 and a locking portion 69 which is heavier than the tripping arm and normally urges the locking member to the position shown in FIG. 4. In this normal position, the tripping arm 68 extends into the path of tray movement in advance of a tray engaged by the driving dog 61 of the pusher unit; and, the portion 69 of the locking member 56 engages a horizontal surface 70 and a shoulder or abutment 72 on the positioning arm 64 of the pusher member 54. The shoulder 72 defines the nonnal position of the locking member 56, and also prevents movement of the locking member from this position in one direction. Thus, the locking member 56 will move from the normal position to a released position when the pusher unit overtakes an object in the path of travel of the tripping arm 68 of the locking member 56, and permit the pusher member 54 to move from the driving position to a non-driving position in which the driving dog 61 is disengaged from the driving means 28 of a tray. However, the locking member 56 will not move from normal position if overtaken by an object such as a tray but instead will function as a holdback member,

When the pusher member 54 and locking member 56 are in their normal positions and the driving dog 61 is engaging and moving a tray along the rails 12 and 14, the reaction force against the driving dog 61 tends to move the pusher member 54 to non-driving position and is resisted by engagement between the surface 70 on the pusher member positioning arm 64 and a lobe 74 on the locking portion 69 of the locking member 56. This lobe 74 is in an over-center position relative to the locking member pivot 58 and the reaction force transmitted to the locking member by the pusher member tends to retain the locking member in normal position against the abutment 72. A slight amount of pivotal movement of the locking member resulting from engagement of the tripping arm 68 with an object in the path of travel will move the lobe 74 past a dead center position in the releasing direction of motion, and the releasing action will then be augmented by the driving reaction force.

In FIG. 4, the pusher unit 38 is shown with the tripping arm 68 of the locking member projecting into the path of movement of a tray 10, with the driving means 28 adjacent the end 30 of this tray engaged by the driving dog 61, and initially contacting the end 31 of a preceeding tray which may be assumed to be stopped. Further forward movement 59 of the pusher unit will result in the rapid releasing action described above, the driving dog 61 will disengage from the driving means of the tray being propelled, and the locking member 56 will be retained in released position by contact of the tripping arm 68 with the bottom 26 of the preceeding tray.

The same releasing action can be obtained by employing a stopping device (not shown) mounted on the tray supporting structure and having a surface engageable by the tripping arm 68 for a distance greater than the distance between the tripping arm 68 and driving dog 61 along the length of the conveyor. Thus, trays can be stopped and automatically accumulated as desired.

Ascending and descending vertical curves can also be used, as desired. On a descending vertical curve where a, tray might overrun a pusher unit, the spacing shown in FIG. 4 between the track 46 and the tray supporting plane defined by the rails 12 and 14 may be decreased to position the holdback dog 62 in overlapping relation with the end 30 of the tray; alternately or additionally, the tripping arm 68 may be lengthened for hold back action.

Referring to FIG. 1, the conveyor construction illustrated includes a horizontal curve 76 and a junction 78 where operation of a diverter member 80 will result in a tray 10 being transferred from a forwarding pusher unit 38, travelling in the direction 81 along the path indicated by the broken line 82, to a branch line 84 having receiving pusher units 38 on a propelling member supported in a track 85 and traveling in the direction 86 along the path indicated by the broken line 87.

Approaching the horizontal curve 76, the propelling member track 46 is provided with a portion 88 off-set toward the inner radius of the curve which places the driving dog 61 of a pusher member in engagement with one of the angular side portions 34 of the driving means 28 of a tray, and following the horizontal curve 76 the propelling member track 46 is again off-set to return the path of pusher travel to a centered position. These angular side portions 34 of the tray driving means 28 also aid in the transfer of a tray from a forwarding to a receiving pusher unit. The tray 10 shown at the junction 78 in FIG. 1 has been moved laterally and obliquely by the action of the diverter 80 to a position where the driving dog 61 of a forwarding pusher unit 38 has wiped off the angular side portion 34 of the driving flange 28 and the tray has been diverted laterally a distance sufficient for engagement by a driving dog of a receiving pusher unit 38 traveling in the path 86 with the driving means 28 at the other side of the tray. Positive driving action, particularly by the driving dog of the forwarding pusher unit, is enhanced by the angular side portion 34 of the driving means which compensates for the oblique positioning of the tray relative to the path of pusher movement.

I claim:

1. In a pusher conveyor system for trays, the combination of:

a plurality of trays, each tray having a bottom portion with driving means thereon;

tray supporting and guiding structure defining a path of tray travel;

a propelling member and means mounting the propelling member for travel below the bottom portion of trays on the tray supporting structure;

a plurality of pusher units and bracket means connecting each of the pusher units to the propelling member in spaced relation along the length thereof;

each pusher unit comprising a pusher member and a locking member, the pusher member having a driving dog and a positioning arm, and the locking member having a locking portion and a tripping arm;

the bracket means supporting the pusher member for movement between a normal driving position in which the driving dog is engageable with the driving means on a tray and a non-driving position, and separately supporting the locking member for movement between a normal locking position in which the locking portion prevents movement of the positioning arm of the pusher member to non-driving position and a released position in which the pusher member is movable to non-driving position;

the tripping arm of the locking member in locking position extending into the path of tray movement in advance of a tray whose driving means is engaged by the driving dog of the pusher member.

2. A pusher conveyor system according to-claim 1 wherein the pusher member and locking member are supported by the bracket means for pivotal movement on separate axes spaced longitudinally of the propelling member, the pivotal axis of the locking member being located in advance of the pivotal axis of the pusher member with relation to the forwarding direction of conveyor movement.

3. A pusher conveyor system according to claim 1 wherein the positioning arm of the pusher member is provided with an abutment engageable by the locking member to define the normal locking position thereof and prevent movement in one direction of the locking member from the locking position.

4. A pusher conveyor system according to claim 1 wherein the positioning arm of the pusher acts as a counterweight to urge the pusher member to the normal driving position and the locking portion of the locking member acts as a counterweight to urge the locking member to the normal locking position.

5. A pusher conveyor system according to claim 1 wherein the driving means on each tray comprises a recessed shoulder formed in the bottom of the tray and extending transversely between the sides thereof.

6. A pusher conveyor system according to claim 5 including a junction between main and branch line, each line having a propelling member and pushers, the propelling members of the main and branch lines at the junction being spaced transversely a distance less than the transverse length of the driving means on a tray, and a tray deflector positionable to shift a tray forwarded on one line laterally into a position for engagement of the driving means by a pusher of the other line.

7. A pusher conveyor system according to claim 5 wherein the recessed shoulder includes a center portion extending substantially normal to the longitudinal center line of the tray and a pair of angular side portions which converge in the direction of travel of the tray on the pusher conveyor.

8. A pusher conveyor system according to claim 7 including a junction between main and branch lines, each line having a propelling member and pushers, the propelling members of the main and branch lines at the junction being spaced transversely a distance less than the transverse length of the driving means on a tray, and a tray deflector positionable to shift a tray forwarded on one line laterally into a position for engagement of the driving means by a pusher of the other line, the angular side portions of the driving means compensating for the oblique positioning of a tray relative to the path of travel of a pusher unit during transfer.

9. A pusher conveyor system according to claim 7 including a horizontal curve section in the tray supporting and guiding structure, the means mounting the propelling member including a track which is offset towards the inner radius of the horizontal curve section to define a path of pusher member travel in which one of the angular side portions of the driving means on a tray is engageable by a pusher member.

10. A pusher conveyor system according to claim 1 wherein the means mounting the propelling member comprises a tubular track in which the propelling member is confined, the track having a continuous slot along one vertical side thereof, and the bracket means connecting each pusher unit to the propelling member including an arm connected to the propelling member and projecting laterally through the slot.

11. In a conveyor system having pusher units connected to a propelling member in spaced relation along the length thereof for forwarding load carriers along a support, the improvement wherein:

each pusher unit comprises a pusher member and a locking member, the pusher member having a driving dog and a positioning arm, and the locking member having a locking portion and a tripping arm;

bracket means connected to the propelling member supports the pusher member for movement between a normal driving position in which the driving dog is engageable with a load carrier and a non-driving position, and separately supports the locking member for movement between a normal locking position in which the locking portion prevents movement of the positioning arm of the pusher member to non-driving position and a released position in which the pusher member is movable to nondriving position; and,

the tripping arm of the locking member in locking position and the driving dog of the pusher member in driving position each project toward the carrier support with the tripping arm being located forwardly of the driving dog with relation to the forwarding direction of movement of the propelling member.

12. A conveyor system according to claim 11 wherein the pusher member and locking member are supported by the bracket means for pivotal movement on separate axes spaced longitudinally of the propelling member, the pivotal axis of the locking member being located in advance of the pivotal axis of the pusher member with relation to the forwarding direction of movement of the propelling member.

13. A conveyor system according to claim 11 wherein the positioning arm of the pusher member is provided with an abutment engageable by the locking member to define the normal locking position thereof and prevent movement in one direction of the locking member from the locking position.

14. A conveyor system according to claim 11 wherein the positioning arm of the pusher acts as a counter weight to urge the pusher member to the normal driving position, and the locking portion of the locking member acts as a counter weight to urge the locking member to the normal locking position. 

1. In a pusher conveyor system for trays, the combination of: a plurality of trays, each tray having a bottom portion with driving means thereon; tray supporting and guiding structure defining a path of tray travel; a propelling member and means mounting the propelling member for travel below the bottom portion of trays on the tray supporting structure; a plurality of pusher units and bracket means connecting each of the pusher units to the propelling member in spaced relation along the length thereof; each pusher unit comprising a pusher member and a locking member, the pusher member having a driving dog and a positioning arm, and the locking member having a locking portion and a tripping arm; the bracket means supporting the pusher member for movement between a normal driving position in which the driving dog is engageable with the driving means on a tray and a non-driving position, and separately supporting the locking member for movement between a normal locking position in which the locking portion prevents movement of the positioning arm of the pusher member to non-driving position and a released position in which the pusher member is movable to non-driving position; the tripping arm of the locking member in locking position extending into the path of tray movement in advance of a tray whose driving means is engaged by the driving dog of the pusher member.
 2. A pusher conveyor system according to claim 1 wherein the pusher member and locking member are supported by the bracket means for pivotal movement on separate axes spaced longitudinally of the propelling member, the pivotal axis of the locking member being located in advance of the pivotal axis of the pusher member with relation to the forwarding direction of conveyor movement.
 3. A pusher conveyor system according to claim 1 wherein the positioning arm of the pusher member is provided with an abutment engageable by the locking member to define the normal locking position thereof and prevent movement in one direction of the locking member from the locking position.
 4. A pusher conveyor system according to claim 1 wherein the positioning arm Of the pusher acts as a counterweight to urge the pusher member to the normal driving position and the locking portion of the locking member acts as a counterweight to urge the locking member to the normal locking position.
 5. A pusher conveyor system according to claim 1 wherein the driving means on each tray comprises a recessed shoulder formed in the bottom of the tray and extending transversely between the sides thereof.
 6. A pusher conveyor system according to claim 5 including a junction between main and branch line, each line having a propelling member and pushers, the propelling members of the main and branch lines at the junction being spaced transversely a distance less than the transverse length of the driving means on a tray, and a tray deflector positionable to shift a tray forwarded on one line laterally into a position for engagement of the driving means by a pusher of the other line.
 7. A pusher conveyor system according to claim 5 wherein the recessed shoulder includes a center portion extending substantially normal to the longitudinal center line of the tray and a pair of angular side portions which converge in the direction of travel of the tray on the pusher conveyor.
 8. A pusher conveyor system according to claim 7 including a junction between main and branch lines, each line having a propelling member and pushers, the propelling members of the main and branch lines at the junction being spaced transversely a distance less than the transverse length of the driving means on a tray, and a tray deflector positionable to shift a tray forwarded on one line laterally into a position for engagement of the driving means by a pusher of the other line, the angular side portions of the driving means compensating for the oblique positioning of a tray relative to the path of travel of a pusher unit during transfer.
 9. A pusher conveyor system according to claim 7 including a horizontal curve section in the tray supporting and guiding structure, the means mounting the propelling member including a track which is offset towards the inner radius of the horizontal curve section to define a path of pusher member travel in which one of the angular side portions of the driving means on a tray is engageable by a pusher member.
 10. A pusher conveyor system according to claim 1 wherein the means mounting the propelling member comprises a tubular track in which the propelling member is confined, the track having a continuous slot along one vertical side thereof, and the bracket means connecting each pusher unit to the propelling member including an arm connected to the propelling member and projecting laterally through the slot.
 11. In a conveyor system having pusher units connected to a propelling member in spaced relation along the length thereof for forwarding load carriers along a support, the improvement wherein: each pusher unit comprises a pusher member and a locking member, the pusher member having a driving dog and a positioning arm, and the locking member having a locking portion and a tripping arm; bracket means connected to the propelling member supports the pusher member for movement between a normal driving position in which the driving dog is engageable with a load carrier and a non-driving position, and separately supports the locking member for movement between a normal locking position in which the locking portion prevents movement of the positioning arm of the pusher member to non-driving position and a released position in which the pusher member is movable to non-driving position; and, the tripping arm of the locking member in locking position and the driving dog of the pusher member in driving position each project toward the carrier support with the tripping arm being located forwardly of the driving dog with relation to the forwarding direction of movement of the propelling member.
 12. A conveyor system according to claim 11 wherein the pusher member and locking member are supported by the bracket means for pivotal Movement on separate axes spaced longitudinally of the propelling member, the pivotal axis of the locking member being located in advance of the pivotal axis of the pusher member with relation to the forwarding direction of movement of the propelling member.
 13. A conveyor system according to claim 11 wherein the positioning arm of the pusher member is provided with an abutment engageable by the locking member to define the normal locking position thereof and prevent movement in one direction of the locking member from the locking position.
 14. A conveyor system according to claim 11 wherein the positioning arm of the pusher acts as a counter weight to urge the pusher member to the normal driving position, and the locking portion of the locking member acts as a counter weight to urge the locking member to the normal locking position. 